Hepatic Endometriosis With Diaphragmatic and Pulmonary Invasion Treated by En Bloc Resection: A Case Report

A 54-year-old woman with a medical history of pyelonephritis, dengue fever, laparoscopic resection of infiltrating endometriosis involving the left ureter and an end-to-end anastomosis, and Lyme-associated meningitis/encephalitis presented with severe right upper abdominal quadrant and right shoulder pain. A small liver lesion of 3–4 mm was diagnosed with plans to follow up over time. Because of persistent right shoulder pain, regular analgesics and morphine were prescribed. The patient received hormone therapy with estradiol patches, combined with a levonorgestrel-releasing intrauterine device (Mirena) as the progestogenic component for endometrial protection during systemic estrogen therapy. She then presented to the emergency department of another hospital with exacerbated abdominal pain and vomiting, leading to hospital admission. Laboratory values were unremarkable. Contrast-enhanced computed tomography (CT) scan demonstrated a large multiloculated, blood-containing cystic lesion in hepatic segment VIII with enhancing surrounding soft tissue, abutting the diaphragm with suspicion of extension into the right lung (Figs. 1 and 2 ). Compared with earlier scans, the lesion was significantly increased. Differential diagnosis included complicated giant hemangioma, cystic hepatic neoplasm, atypical endometriosis, echinococcosis, and malignant transformation given the suspected diaphragmatic and pulmonary invasion. Tumor markers (AFP, CA-125) were within reference ranges, and echinococcus serology was negative. Although predominantly hemorrhagic and cystic, the lesion contained areas suitable for percutaneous sampling, and biopsy was performed to guide management. Histopathology confirmed hepatic endometriosis in the right hepatic lobe. van de Laar. Hepatic Endometriosis With Lung Invasion. O&G Open 2026 . van de Laar. Hepatic Endometriosis With Lung Invasion. O&G Open 2026 . Subsequently, the patient was referred to our hospital where further multidisciplinary discussions were conducted involving gynecologists, infectious disease specialists, hepatobiliary surgeons, and cardiothoracic surgeons. Although biopsy confirmed hepatic endometriosis, the rapid lesion growth and radiologic suspicion of diaphragmatic and pulmonary invasion suggested that malignant transformation could not be excluded, supporting complete resection according to oncologic principles. Ultimately, after extensive counseling and multidisciplinary consultation, a decision was made to proceed with surgical intervention. Estrogen patch therapy wasdiscontinued. Through a subcostal incision, a cholecystectomy was performed to facilitate hilar exposure which is standard practice because the gallbladder is located in the resection plane of a hemihepatectomy. A right hemihepatectomy was then performed with division of the right hepatic artery, portal vein, right-sided biliary structures, short hepatic veins, and right hepatic vein. The right lobe remained attached only to the involved diaphragm. The diaphragm was circumferentially opened with a 1-cm margin. After macroscopic confirmation of involvement of the right lower lung lobe, right lung ventilation was suspended and wedge resection was performed with a stapling device without disrupting the en bloc specimen (Fig. 3 ). Pulmonary integrity was confirmed with a water leak test, after which right lung ventilation was re-established. The 6- to 8-cm diaphragmatic defect was reinforced with an OviTex mesh. Thoracic and abdominal drains were placed, and the liver remnant was fixed to the diaphragm. Operative time was 410 minutes with 600 mL blood loss. van de Laar. Hepatic Endometriosis With Lung Invasion. O&G Open 2026 . Histopathologic examination revealed extensive endometriosis infiltrating the liver, diaphragm, visceral pleura, and lung parenchyma, with clear surgical margins and no malignancy (Figs. 4 and 5 ). Gallbladder and pleural biopsies were benign. van de Laar. Hepatic Endometriosis With Lung Invasion. O&G Open 2026 . van de Laar. Hepatic Endometriosis With Lung Invasion. O&G Open 2026 . Broad-spectrum antibiotics were continued for 48 hours. The initial postoperative course was uneventful, and drains were removed on postoperative day 4. On day 6, the patient developed fever, and CT imaging showed reactive intraperitoneal fluid, bilateral pleural effusions, and a small right pneumothorax. Piperacillin–tazobactam was started, and a right pleural drain was inserted, yielding 700 mL sterile serous fluid. Drain fluid was collected and sent for culture, but no positive culture was present. Antibiotics and drainage were discontinued after 3 days, and she was discharged on postoperative day 8 to a step-down care facility. Postoperative opioids were tapered and discontinued by week 8. Follow-up imaging showed gradual resolution of pleural fluid. Four-month CT confirmed complete resolution, an intact diaphragmatic mesh, and no vascular or biliary complications (Fig. 6 ). At 1 year, she remained well and recurrence free.

This case demonstrates that hepatic endometriosis, although benign, may show locally invasive behavior with extension through the diaphragm into the lung. To the best of our knowledge, this is the first reported case of hepatic endometriosis breaching the diaphragm with pulmonary involvement. Although hepatic and thoracic endometriosis have each been described separately, cases of both together in one patient are rare. 13 For our patient, the path to diagnosis and definitive treatment was prolonged and marked by debilitating shoulder pain requiring escalating opioid therapy. Complete en bloc resection of the right hemiliver, diaphragm, and part of the right lower lung lobe resulted in clear margins, symptom resolution, and no recurrence at 1 year. The diagnosis of hepatic endometriosis is challenging because imaging findings are nonspecific and may mimic infectious, benign, or malignant cystic liver lesions. Imaging should be tailored to the suspected site of disease; hepatic and thoracic involvement generally requires dedicated liver magnetic resonance imaging and CT in selected cases to define lesion morphology and local extension. Histopathologic confirmation remains essential to establish the diagnosis and to exclude malignancy or infection. This case highlights that biopsy-proven hepatic endometriosis should not automatically be considered indolent when imaging suggests rapid growth or transdiaphragmatic extension. The pathogenesis of hepatic endometriosis remains poorly understood, and proposed mechanisms include retrograde menstruation, coelomic metaplasia, lymphatic or hematogenous dissemination, and neonatal uterine bleeding. 1 Hepatic or thoracic spread of the endometrial sites suggests a vascular or lymphatic spread to reach sites that are not or hardly reachable through intraperitoneal spread. However, the heterogeneity of extrapelvic endometriosis and the different contexts in which it develops suggest that a single etiopathogenetic model is not sufficient to explain its complex pathobiology. 11 , 14 In our case, it is most likely that the endometriosis spread to the liver and behaved invasively by breaching through the diaphragm into the right lower lung lobe. Alternatively, a primary peritoneal localization at the peritoneal reflection between diaphragm and liver could have been possible. Bouras et al 15 previously reported a comparable case of hepatic endometriosis invading the left diaphragm and right ventricle also requiring combined hepatobiliary and thoracic en bloc resection. No guidelines exist for the optimal management of hepatic endometriosis. 11 In the largest review to date, including 32 cases, treatment consisted of cyst enucleation in 45%, minor hepatectomy in 29%, and major hepatectomy in 26%, with generally favorable outcomes. 5 Approximately 40% of patients were diagnosed after menopause, and estrogen supplementation has been reported in some postmenopausal cases, including ours. Whether exogenous estrogen contributed to the invasive behavior in our patient remains speculative; lesion growth is likely influenced by complex hormonal, angiogenic, and genetic factors. 1 In the series by Prodromidou et al, 5 right upper quadrant or epigastric pain was the leading symptom, and imaging typically showed multiloculated cystic or mixed lesions mimicking hydatid cysts, hemangiomas, cystadenomas, cystadenocarcinomas, or metastases. Preoperative diagnostic accuracy was below 33%, supporting histopathology as the diagnostic cornerstone. Fewer than 40 cases of hepatic endometriosis have now been reported worldwide. 8 , 11 , 12 , 16 Although extragonadal malignant transformation of endometriosis is extremely rare, invasive behavior should raise suspicion. 11 In our patient, radiologic invasion into the diaphragm and lung did not exclude malignancy; therefore, en bloc resection with clear margins according to oncologic principles was considered appropriate. Although cryoablation has been described for extrauterine endometriosis, it was considered unsuitable in this case because suspected malignant behavior required complete resection and histopathologic assessment. 17 Malignant transformation is generally diagnosed by demonstrating adjacent benign endometriosis, endometrial-type malignancy, and exclusion of another primary tumor. 18 Surveillance after resection of suspected malignant endometriosis is recommended, although its optimal duration is unclear. 19 Given the absence of malignant features and radical resection, 1 year of recurrence-free follow-up was considered adequate in our case. Although robotic approaches have been described for selected diaphragmatic endometriosis lesions, 20 the combined hepatic, diaphragmatic, and pulmonary involvement in our patient justified an open transdiaphragmatic approach. This case supports early multidisciplinary evaluation involving radiology, gynecology, hepatobiliary–pancreatic surgery, thoracic surgery, and infectious diseases when hepatic endometriosis is suspected. Hepatic endometriosis should be included in the differential diagnosis for cystic or hemorrhagic hepatic lesions. This report is the first to document diaphragmatic and pulmonary invasion from a primary hepatic focus, successfully managed by combined hepatobiliary–pancreatic and thoracic surgery. Early multidisciplinary assessment, histopathologic confirmation, and complete but organ-sparing resection can yield excellent outcomes.